A series of 24 patients with a documented diagnosis of non-Hodgkin's extranodal lymphoma (ENL) involving head and neck sites (excluding the cranial cavity) has been studied. In view of recent advances in the diagnosis of lymphoma, a retrospective histopathological review has been undertaken to place all patients in standardized classifications for morphology (the working formulation) and immunology (Kiel). This resulted in a change of diagnosis from non-Hodgkin's lymphoma in four. The histopathology of these four cases, and the implication of such changed diagnoses are discussed. Of the 20 patients confirmed as having non-Hodgkin's ENL, 16 had primary ENL and four had an ENL focus secondary to disease elsewhere. Three patients in this series had an initial diagnosis made of another malignancy, but histopathological review prior to treatment changed the diagnosis to ENL. Details of presentation, pretreatment evaluation, immunohistochemistry, treatment and course have been analysed. The principal treatment policy for primary ENL has been radiotherapy. Of the 12 patients who received this treatment ten achieved a complete response (83 per cent). Eight remain free of disease at the time of writing. The role of adjuvant chemotherapy is also considered.